The pursuit of new drug entities derived from plants and plant products for various therapeutic applications has its origins in antiquity and continues to the present. One such source is mastic, also known as gum mastic or mastic gum, which is a tree resin obtained as an exudate from Pistacia lentiscus L., a member of the family Anacardiaceae. Mastic was used in the ancient Mediterranean world for gastrointestinal disorders such as gastralgia, dyspepsia and peptic ulcer. Oral administration of mastic to human patients with duodenal ulcer and to experimental rats with induced gastric and duodenal ulcers has been disclosed to have therapeutic effects (Al-Habbal et al (1984) Clin Exp Pharmacop Physio 11(5):541-4; Said et al (1986) J Ethnopharmacol 15(3):271-8). While it has been disclosed that mastic has in vitro bactericidal effects against Helicobacter pylori, the etiologic agent causing peptide ulcer disease (Marone et al (2001) J Chemother 13:611-614), other reports disclose that mastic does not exert anti-bacterial activity upon administration to H. pylori positive human patients (Bebb et al (2003) J Antimicrob Chemother 52:522-23) or to experimentally infected mice (Loughlin et al (2003) J Antimicrob Chemother 51:367-371).
Greek Patent No. GR 1,003,541 discloses antimicrobial and antifungal action of the chios mastic oil extracted from the leaves, branches and fruit of Pistacia lentiscus var Chia. Greek Patent No. GR 1,003,868 discloses use of a product derived from Pistacia lentiscus var. Chia as an antioxidant, as a wound healing inductor and as a cytostatic agent.
U.S. Patent Application Publication No 2005/0238740 discloses that certain fractions extracted from mastic resin exhibit anti-microbial and anti-cell proliferative activities. According to the disclosure, a first extract (termed “total fraction” or “whole extract”) contains all the compounds of the mastic gum except the polymer resin; a second extract is an acid fraction containing all the triterpenic acids of the total fraction, and a third extract is a neutral fraction containing all the other terpenes of the total fraction. Additionally disclosed is an essential oil obtained by distillation which contains monoterpenes including β-myrcene. The application discloses pharmaceutical formulations comprising any of the aforementioned total, acid or neutral fractions optionally combined with the essential oil, or synthetic equivalents thereof, or comprising isolated component products or synthetic equivalents thereof, as well as the use thereof in methods for treating microbial infections including H. pylori, Propionibacterium, Staphlococcus, Pseudomonas, and cell hyperproliferation. Paraschos et al (2007), authored by some of the inventors of the aforementioned patent application, disclose preparation of a total mastic extract without polymer (TMEWP), prepared by polar solvent extraction of crude mastic and removal of the insoluble polymer poly-β-myrcene therefrom, and acidic and neutral fractions separated from TMEWP (Paraschos et al (2007) Antimicrob Agents, Chemother 51(2):551-559). According to the disclosure, administration of TMEWP to H. pylori infected mice over a period of 3 months resulted in a 30-fold reduction of bacterial colonization, largely attributable to a particular compound purified from the acid fraction. The authors indicate that TMEWP was prepared since the high percentage of poly-β-myrcene in crude mastic preparations, as used in previous studies, was speculated to hinder potential in vivo activity during oral administration. The authors further disclose that removal of the poly-β-myrcene produces an enhanced therapeutic moiety with anti-H. pylori activity.
EP Patent Application No. 1520585 discloses use of a product obtained from a plant of the genus Pistacia for the manufacture of a medicament for treating or preventing cancer. According to the disclosure, essential oils distilled from leaves, twigs, fruits, nuts and flowers of different Pistacia species contain a large number of monomeric terpene compounds in varying proportions inter alia β-myrcene. The application further discloses that the oils have activity against certain tumor cells lines such as colon and ovary adenocarcinomas, and that bornyl acetate was the only single component found to have anti-cancer activity.
International Patent Application Publication No. WO 2005/112967 discloses the purification from mastic of anti-cancer material having anti-proliferative effects, which is found in a soluble fraction obtained by suspending mastic in a solvent selected from a non-acidic, aliphatic hydrocarbon, an aqueous solution containing at least 25% of a water-soluble, non-acidic, aliphatic hydrocarbon, or a combination thereof, and removing the insoluble fraction. The application further discloses a method for treating cancer cells comprising administering a pharmaceutically effective amount of a fraction of mastic gum resin that inhibits growth of cancer cells. According to the disclosure, the anti-cancer compound is effective against various types of cancer cells, including human colon cancer cells.
Van der Berg et al (1998) disclose isolation and purification of the polymer fraction of mastic using extraction and size exclusion chromatography (Van der Berg et al (1998) Tetrahedron Lett 3:2645-2648). According to the disclosure, the polymer has a broad molecular weight distribution i.e. 20,000 to 100,000 Da, is formed from monomer units of 136 Da, and has the structure of 1,4-poly-β-myrcene, with cis- and trans-configurations at a ratio of 3:1. The authors assert that their disclosure is the first report of a naturally occurring polymer of a monoterpene.
Barra et al (2007) disclose extraction and gas chromatographic analysis of essential oil from P. lentiscus L. (Barra et al (2007) J Agric Food Chem 55(17):7093-7098). According to the disclosure, a total of 45 compounds were identified, including β-myrcene as one of the major compounds. Marner et al (1991) disclose identification of various triterpenoids from gum mastic of P. lentiscus (Marner et al (1991) Phytochemistry, 30, 3709-3712).
U.S. Pat. No. 5,506,406 discloses mastic oil produced by dissolving mastic in an oil or fat, and filled in a soft capsule which optionally further contains an amphipathic substance such as chitin or chitosan. According to the disclosure, the capsule is effective for eliminating and inhibiting H. pylori, and for reducing the smell of feces.
U.S. Pat. No. 5,637,290 discloses an oral hygiene product comprising the combination of a toothpaste and an ingredient selected from natural mastic, extracted mastic oil and synthetic mastic oil agents. Also disclosed is use of mastic for incorporation into suntan lotion, hair products and cosmetics.
U.S. Pat. No. 6,623,728 discloses cosmetic skin care emulsion compositions comprising from about 0.001 wt % to about 10 wt % solubilized gum mastic; a volatile water miscible solvent; and a cosmetically acceptable vehicle. According to the disclosure, the emulsion is preferably an oil-in-water emulsion, and preferred solvents include ethanol, methanol propanol, isopropyl alcohol and mixtures thereof. According to the disclosure, the same types of solvents are used to obtain the solubilized gum mastic.
U.S. Pat. No. 6,811,769 discloses an oral composition comprising an oil extract of mastic, such as that prepared with olive oil or palm oil; and an antiphlogistic, such as glycyrrhizic acid. According to the disclosure, the composition has antibacterial action against periodontal disease-related bacteria and against tooth decay-related bacteria.
U.S. Pat. No. 7,294,651 discloses use of isoprenoid compounds, inter alia terpene compounds for inhibiting the production of exoproteins of Gram positive bacteria, such as Toxic Shock Syndrome Toxin-1 produced by S. aureus. According to the disclosure, suitable terpenes may be cyclic or acyclic, saturated or unsaturated, and also include inter alia polyterpenes. Also disclosed is the use of such compounds for preparing compositions which may be incorporated into aqueous solutions, such as vaginal cleaning formulations.
U.S. Pat. No. 4,564,718 discloses preparation of functionally terminated polymers, referred to as “liquid rubbers” having glass transition temperatures substantially less than room temperature, by polymerization of a terpene or oxygen derivative thereof having a double bond or conjugated double bond available for polymerization, with an initiator which provides the desired functional termination. According to the disclosure, the polymers preferably have a molecular weight of 500 to 20,000, and preferred acyclic monoterpenes for preparation thereof are inter alia β-myrcene. The patent discloses preparation of polymeric myrcene of molecular weight of about 2000 and of about 4000. The patent further discloses that the polymers of the invention may be further reacted with other reagents to provide elastomers, sealants or adhesives, or they may be used as rubber toughening agents. Further disclosed is preparation of hydroxy-terminated polymyrcene from myrcene, and use thereof to prepare a polyurethane elastomer.
Newmark et al J. Polymer Sci 26, 71-77 (1988) discloses synthesis of polymyrcene having an observed molecular weight of 87,000 and a calculated molecular weight of 46,000.
U.S. Pat. No. 4,374,957 discloses a tacky thermoplastic elastomeric linear triblock polymer corresponding to the formula A-B-A, wherein A is a nonelastic linear homopolymer block of a monovinyl aromatic hydrocarbon having an average molecular weight between 10,000 and 60,000 and a glass transition temperature above 70° C., and wherein B is an elastomeric homopolymeric block of myrcene having an average molecular weight between 50,000 and 200,000 and a glass transition temperature below about −40° C.
U.S. Pat. No. 5,759,569 discloses biodegradable compostable articles that at least partially comprise certain trans-polymers, wherein the polymers have a weight average molecular weight of at least about 20,000 and are made by polymerizing a monomer component that comprises: (1) from about 70 to 100 mole % 1,3-dienes inter alia β-myrcene; and (2) up to about 30 mole % other compatible comonomers. According to the disclosure, the articles include inter alia packaging materials; disposable absorbent articles (e.g., diapers, sanitary napkins); garment articles such as protective clothing, surgical drapes, surgical gowns, surgical sheets; woven, knitted and non-woven fabrics; surgical sponges, tampon applicators, disposable syringes and containers.
U.S. Pat. Nos. 7,232,872 and 7,214,750 disclose a polymerization process comprising contacting one or more monomer(s) inter alia myrcene, one or more Lewis acid(s), one or more initiator(s), and a diluent comprising one or more hydrofluorocarbon(s) in a reactor.
U.S. Patent Application Publication No 2007/0179260 and U.S. Pat. No. 7,417,103 disclose 3,4-isoprene-based polymers with high regioregularity and a method for producing same. According to these disclosures, the number average molecular weight of the polymer is 5000 to 6,000,000, and the polymer may also include units of 1,4-isoprenes such as myrcene. According to the disclosure, the polymer is suitable for use as a plastic material due to its mechanical and thermal durability.
The prior art does not disclose the use of mastic gum or fractions thereof for treating neurological conditions. The prior art does not teach or suggest use of any isolated fractions of mastic gum in a composition for treating neurological conditions The prior art also does not teach or suggest the advantageous use of an isolated fraction of polymeric myrcene, whether that derived from mastic, or that chemically synthesized, as an active ingredient in a pharmaceutical composition or in a therapeutic application.